120-CCPM
Setup
Spektrum
DX7
last updated 11-22-2008
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120-CCPM
Setup |
| Step 1: Setup radio for CCPM | Enter the system menu by holding both 'DOWN' and 'SELECT' buttons while you turn the radio on. Use the 'DOWN' button to get to [SWASH TYPE]. Next press the 'DECREASE' button to change the type to '3 SERVO - 120'. Exit the system menu by holding both 'DOWN' and 'SELECT' buttons at the same time. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Step 2: Connect the servos | In the manual you see the diagram like the one at the
bottom. Note the servos are positioned such that Ch2
& Ch6 are at the front of the helicopter (but control
the back of the swashplate) and the servo for the
elevator/Ch3 is at the back of the helicopter. Connect the servo at the front-left to Ch2 (AILE on the receiver). Connect the servo at the front-right to Ch6 (AUX 1 on the receiver). Connect the servo at the back to Ch3 (ELEV on the receiver). 
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| Step 3: activate throttle hold | Go to [THRO HOLD] and if it has INH in the middle of
the screen then press the 'INCREASE' button to activate
the hold function. Set the 'HOLD POS.' to 15%. Later you
will adjust this value to give a good idle while the hold
switch is flipped. Pull the throttle hold switch toward you. This will put the radio in HOLD mode and you will note that when you go to [PITCH CURVE - HOLD] that the 'HOLD' will flash indicating it is in that mode. Note: If you have the throttle hold switch pulled toward you when you turn the radio on it will beep at you indicating that the radio is in throttle hold mode. Why the programmer did this on the DX7 I do not know. I understand it beeping at you if you have it in flight mode 1 or 2 but it should not for throttle hold... |
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| Step 4: set the pitch curve |  In the menu select [PITCH CURVE
- HOLD]. Set the pitch curve points-L,1,2,3,H to 0,50,50,50,100.
The reason you set the middle three points to 50 is so
you do not have to wonder if you have the collective
stick exactly in the center during the setup. |
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| Step 5: set end points |  In the menu go to [TRAVEL ADJUST]
then set the end points of the collective (PIT), aileron
(AILE), and elevator (ELEV) to 100% both directions. Use
the SELECT button to get to the AILE, ELEV, and PIT. The
PIT. is on the second page, just keep pressing SELECT to
get to it. When you are on each servo selection you use
the corresponding stick to move between L/R, D/U, H/L. In
other word for the collective pitch you would move the
collective/throttle stick all the way up then adjust the
value using the INCREASE/DECREASE buttons to set the
value to 100%. Then move the stick all the way down and
set that value also to 100%. Since you are setting the
values to the default of 100 you can press the 'clear'
button instead. |
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| Step 6: zero the sub-trim | Go to [SUB TRIM] and press 'select' button to get to AILE, ELEV, and PIT and set each to 0. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Step 7: center the trims | On the startup screen you can see the position of the trims. These are the bars along the left, right, and bottom of the display. Move the aileron and elevator trims so they are centered. You should do this also for Normal, flight mode 1&2, and throttle hold. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Step 8: Servo direction | With the radio on and the helicopter powered, move
the collective stick up while you watch the rotation of
the servos. As you move the collective up the servo at the front-left needs to rotate counter-clockwise. If not go to [REVERSING SW] and change the value for 'ch 2'. As you move the collective up the servo at the front-right needs to rotate clockwise. If not go to [REVERSING SW] and change the value for 'ch 6'. As you move the collective up the servo at the back needs to rotate clockwise. If not go to [REVERSING SW] and change the value for 'ch 3'. Collective up = ail-CCW ele-CW coll-CW My setup with Hitec servos ended up with values of: AILE: Reverse, ELEV: NORM, PIT.: NORM Move the elevator
stick forward (toward the top of the radio). The back
servo needs to rotate counter-clockwise. If not go to [SWASH
MIX] and reverse the value of 'elevator'. For example if
you have +60 then make it -60. |
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| Step 9: choose a servo arm | For the Aileron, Elevator, and Collective servos you
need to choose a servo arm that has holes close to 14.5mm
from the center. If it is a little off that is fine but
no more then a couple of millimeters. The total distance
between the balls you install on the servo arm should
match the distance between the balls on the levers. I
measured them at 29mm. Note: Do not mount the balls at this time. |
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| Step 10: center the collective stick | If you setup the pitch curve with 0,50,50,50,100 then
you can put the stick anywhere near center and know that
the output to the servo is 50%. However if you have a
straight line curve (0,inh,50,inh,100) then you need to
make sure the stick is exactly centered. Follow the step
below to do this. Go to [PITCH CURVE - HOLD]. Look at the 'IN' value and move thc collective stick to the middle so that the 'IN' value is 50. Note that the OUT value needs to also be 50. If it is not then make sure you do not have a program mix that is effecting the pitch. |
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| Step 11: Mount the servo arms | Now you need to mount the servo arm on each servo.
Note that if the servo arm you use has two or four arms
then before you mount the ball you should try each side
to see which one gives a perfect 90 degree angle (as
shown in the photo below). When you place a servo arm on the spline of the servo you will have to try several positions to find the one that makes the arm straight up/down. If you find the teeth on the spline cause the arm to be offset just a little one way and when you go one notch over then it is off the same amount the opposite direction then rotate the arm 180 degrees and try that. On most servo arms the teeth of the arm are positioned so that the opposite arm will orient right in between.
Once you have found the correct position for each of the servo arms then mount the balls on the arms as close to 14.5mm from center as you can get. Also many times you will find the 'extra' arms that are not being used will interfere with the links. If it does you can cut off the arm as you see I did in the photo on the right. |
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| Step 12: build links |  Links
from front two servos: Use the 61mm rods and
make four links that are 80mm from center of hole to
center of hole. You will need to test this as the links
may need to be shorter or longer depending on your servo.
Each brand of servos have the spline positioned
differently. It is important that both links going to the
servo remain an identical length. First try the 80mm and
if both links do not match both balls on the servo arm
exactly then adjust both links one full turn equally and
try again.Links from back servo: Yes these two are tough. The only tip I have is to take note of how many turns you made on the front links (to adjust for spline position) and do the same to these two after you set it to 32mm. Links to bottom of swashplate: These links are used to do two things. First is to level the swashplate so it is not tilted in any direction and second is to center the swashplate up and down. The manual says the three links going to the bottom ring of the swashplate should be 58.5mm. However I found when these were set there that the swashplate was not centered in the usable travel range. What I mean by usuable travel range is when the swashplate is just above the frame the swashplate will hit when you use the aileron and elevator. So this area is not usable. Look at the table below and you can see the usable travel range.
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| Step 13: Re-check | With the collective stick in the middle: >you have all three servo arms 90 degrees to the links  >and
the levers are in the center position >The swashplate is in the center of the usuable
travel *note: if you have a swashplate leveler you would remove the head and mixing base then place the leveler on top of the swashplate. Use the Aileron, Elevator, and Collective [SUB TRIM] to get the swashplate level. Otherwise you would just eyeball it. Look from the front and the sides to get the swashplate level with the top of the frames. |
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| Step 14: set blades to zero degrees |  There are two
links (per side) that are involved in setting the blade
pitch. In the picture on the right you can see I labeled
them 'long link' and 'short link'. Note in conversations
the short link is often referred to as the 'double link'.
Long Link - This should be adjusted so that the mixing arm is parallel to the flybar WHEN the flybar is 90 degrees to the main shaft as you see in the picture on the right. Short Link - Adjust this link so the blade is zero
degrees. Use a pitch gauge to measure the angle of the
blade relative to the flybar. If you have not used a
pitch gauge then refer to <this>
page. |
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| Step 15: adjust range | In the [SWASH MIX] menu you will see a value for the
'PIT.', 'AILE', and the 'ELEV'. This value represents not
only the direction of travel (positive or negative), but
also how much that function is to move. This replaces the
End Point (EPA, ATV's) that most are use to using to
limit the travel of each servo. Collective Pitch - For the collective pitch move the stick on radio all the way up. Make sure that the mixing base does not hit the bottom of the head block. If so then lower the PIT value. Measure the pitch of the blade at this full up position then check the pitch again at full down. The pitch range you want will depend on the type flying you do. Most people will setup a range of 20 degrees (-10 to +10). However for the latest 3D flying a common range is 26 degrees (-13 to +13). With the collective still up, adjust the PIT value to get 13 degree on the blades. And with the stick down you should get -13. If you find the top and bottom angles are not opposite of each other then it means you did not do Step 14 (zero blade setup) correct. Aileron - With the main blades rotated so they are inline with the tailboom, set the pitch gauge to zero degrees and move the collective stick so the pitch gauge aligns with the flybar. Now hold full right aileron and realign the pitch gauge level with the flybar. This will give you the amount of right aileron cyclic pitch. Check the amount you have for left. If you do not get the opposite value then check into the problem. A common value most want to obtain for the cyclic pitch is 10 degrees. Adjust the AILE value to get this. Elevator - Do the same as you did with the aileron except have the main blades 90 degrees to the tail boom. And use the elevator stick to get the elevator cyclic range. Adjust with the ELEV value. |
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| Step 16: reset the pitch curve | In the previous steps we used a pitch curve that was flat in the middle (0,50,50,50,100). Set the pitch cuve back to the default 0,inh,50,inh,100. Do this by using the select button to highlight curve point '1' and press the clear button. Do the same for curve point '3'. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Step 17: swashplate leveling | Most people stop at the previous step but if you have one of the swashplate levelers then you use it in combination with the [TRAVEL ADJUST] values to level the swashplate when it is at the full up and full down positions. For example lets say the swashplate is level in the center (done in step 13) but at full up the swashplate is tilted forward. You would then go to [TRAVEL ADJUST] and adjust the ELEV value to level the swashplate. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Next... | The CCPM part is now done and you just need to setup
the pitch range you want to run in each flight mode. Here you just put the pitch gauge on and adjust the pitch curves in the radio to get the angles you want. Here are a few typical configurations:
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